This invention relates generally to an air throttle control apparatus for internal combustion engines. In particular, the apparatus is to provide variable and adjustable control over flow characteristics of air to a two-cycle fuel injected engine such as found common in high horsepower outboard marine engines.
Electronic fuel injected internal combustion engines have become quite common in multiple cylinder outboard motors for the creation of higher speeds, whether it be high performance fishing `bass boat` types or for motorboat racing purposes. Typically, these engines are electronic fuel injected having a forward air intake horn and manifold for supplying air to each cylinder. Heretofore, the air is typically throttled by the use of a butterfly-type throttling valve in the air horn. This form of air throttling has been found to be unsatisfactory, in permitting even finer tuning of the engine to accomplish peak torque at specific rpm's. This is especially so in motorboat racing where it is highly desirable to be able to adjust the air flow for particular conditions that exist at the race sight and for racing situations, i.e., time trials versus the race heats.
Slide valves have been used in carburation for internal combustion engines as an alternative to butterfly valves, such as shown in U.S. Pat. No. 4,454,537. Such slide valves have not, however, been able to provide means to change the flow characteristics of the air to the internal combustion engine. Such air flow characteristics include velocity, quantity, and the shape of the air flow.